Re: [PATCH] virtio-scsi: Fix hotcpu_notifier use-after-free with virtscsi_freeze

Re: [PATCH] virtio-scsi: Fix hotcpu_notifier use-after-free with virtscsi_freeze

[Paolo Bonzini]

Il 28/10/2013 09:01, Asias He ha scritto:
> vqs are freed in virtscsi_freeze but the hotcpu_notifier is not
> unregistered. We will have a use-after-free usage when the notifier
> callback is called after virtscsi_freeze.
> 
> Signed-off-by: Asias He <asias@redhat.com>
> ---
>  drivers/scsi/virtio_scsi.c | 15 ++++++++++++++-
>  1 file changed, 14 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
> index 74b88ef..b26f1a5 100644
> --- a/drivers/scsi/virtio_scsi.c
> +++ b/drivers/scsi/virtio_scsi.c
> @@ -957,6 +957,10 @@ static void virtscsi_remove(struct virtio_device *vdev)
>  #ifdef CONFIG_PM
>  static int virtscsi_freeze(struct virtio_device *vdev)
>  {
> +	struct Scsi_Host *sh = virtio_scsi_host(vdev);
> +	struct virtio_scsi *vscsi = shost_priv(sh);
> +
> +	unregister_hotcpu_notifier(&vscsi->nb);
>  	virtscsi_remove_vqs(vdev);
>  	return 0;
>  }
> @@ -965,8 +969,17 @@ static int virtscsi_restore(struct virtio_device *vdev)
>  {
>  	struct Scsi_Host *sh = virtio_scsi_host(vdev);
>  	struct virtio_scsi *vscsi = shost_priv(sh);
> +	int err;
> +
> +	err = virtscsi_init(vdev, vscsi);
> +	if (err)
> +		return err;
> +
> +	err = register_hotcpu_notifier(&vscsi->nb);
> +	if (err)
> +		vdev->config->del_vqs(vdev);
>  
> -	return virtscsi_init(vdev, vscsi);
> +	return err;
>  }
>  #endif
>  
> 

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: stable@vger.kernel.org